CN114883895A

CN114883895A - Ultra-compact light-weight composite cooling type immersion high-energy laser system

Info

Publication number: CN114883895A
Application number: CN202210798567.2A
Authority: CN
Inventors: 易家玉; 阮旭; 胡浩; 曹海霞; 高清松; 唐淳
Original assignee: Institute of Applied Electronics of CAEP
Current assignee: Institute of Applied Electronics of CAEP
Priority date: 2022-07-08
Filing date: 2022-07-08
Publication date: 2022-08-09
Anticipated expiration: 2042-07-08
Also published as: CN114883895B

Abstract

The invention discloses an ultra-compact light-weight composite cooling type immersion high-energy laser system, and relates to the technical field of high-energy lasers. This ultra-compact light weight composite cooling formula immersion high energy laser system includes: the device comprises a laser resonant cavity for generating laser oscillation feedback, an immersion laser gain module for obtaining high gain, and a composite cooling pumping module for outputting pumping light, wherein the immersion laser gain module and the composite cooling pumping module share a set of composite cooling circulating system. Compared with the prior art, the laser system provided by the invention innovatively realizes effective cooling of a multipoint heat source for heat generation of the gain crystal and heat generation of the pumping source by using one set of cooling circulation system, and cools the laser gain medium to ensure effective heat management. On the other hand, the laser system stores the system heat of the multi-point heat source in the thermal phase-change material, thereby greatly improving the compactness of the system while realizing effective heat management and greatly reducing the volume and the weight of the system.

Description

Ultra-compact light-weight composite cooling type immersion high-energy laser system

Technical Field

The invention relates to the technical field of high-energy laser, in particular to an ultra-compact light-weight composite cooling type immersion high-energy laser system.

Background

The high-average-power all-solid-state laser plays an important role in the fields of forward scientific research, national economy, national safety and the like, and is a research hotspot and an important direction in the laser field. The severe thermal effects caused by the increase in laser power are the core problem limiting all-solid-state lasers to achieve high average power, high beam quality laser output. The main oscillation power amplifier is an effective mode for realizing high-power solid laser output, and is commonly a high-power slab amplifier, and the slab amplifier passes through a slab in a zigzag light path to realize aberration self-compensation. However, the heat-generating density of the strip is high, effective heat management is difficult to realize, and the light-transmitting aperture is small, so that a complex 4f system is required to be adopted for phase transmission between each stage of amplification, the light path is complex, the system is huge, and the stability is poor. Therefore, in order to support all-solid-state high-power laser development, new laser amplification configurations need to be adopted.

Immersion liquid cooling is an effective heat management mode, and under the support of the high-efficiency heat management, a plurality of gain media can be arranged in an array mode to achieve distributed gain. The gain mode has the advantages that heat generation is uniformly distributed on the plurality of laser gain media stacked in an array mode, the heat density of the single-chip gain crystal is reduced, and the heat management is effectively realized by adopting a liquid direct cooling mode. However, in the prior art, the laser gain module and the diode pumping source are usually cooled separately, and although the thermal management of the system can be effectively solved, multiple cooling loops are still adopted, so that the laser system is relatively complex, and the application scenarios requiring an ultra-compact laser system are difficult to meet.

Disclosure of Invention

The invention aims to: in view of the above problems, the present invention provides an ultra-compact lightweight composite cooled immersion laser system, which realizes effective thermal management and simultaneously realizes ultra-compactness and miniaturization of the laser.

The technical scheme adopted by the invention is as follows:

an ultra-compact lightweight composite cooled immersion high-energy laser system, the high-energy laser system comprising: the device comprises a laser resonant cavity for generating laser oscillation feedback, an immersion laser gain module for obtaining high gain, and a composite cooling pumping module for outputting pumping light, wherein the immersion laser gain module and the composite cooling pumping module share a set of composite cooling circulating system.

The immersion type laser gain module comprises a plurality of gain medium crystals fixedly stacked in an array mode, a flow channel with a certain thickness is formed among the gain medium crystals, and the surface of each gain medium crystal is cooled through laser cooling liquid flowing in the flow channel.

Gain module heat exchange fins with the same thickness as the gain medium crystal are respectively arranged at the front end and the rear end of the gain medium crystal, and a certain amount of phase change cooling material is stored in each gain module heat exchange fin.

The composite cooling pumping module comprises a pumping source composite cold plate, a tail fiber pumping source transmission optical fiber 5, a circulating pump, a circulating pipeline and a collimation end cap.

And a composite cold plate heat exchange fin is also arranged in the composite cold plate of the pumping source, and a certain amount of phase change cooling material is stored in the composite cold plate heat exchange fin.

The sharing of one set of combined cooling circulation system means that: the pump source composite cold plate and the immersion type laser gain module share laser cooling liquid, the laser cooling liquid flows into the pump source composite cold plate through a circulating pipeline after being cooled by gain module heat exchange fins under the action of a circulating pump (at the moment, heat generated by heat brought out of gain medium crystals is quickly replaced by phase change cooling materials in the heat exchange fins), and meanwhile, heat generated by a tail fiber pump source on the surface of the pump source composite cold plate is absorbed and taken away, and meanwhile, the heat in the tail fiber pump source is transferred and exchanged into the heat phase change cooling materials.

The circulation is repeated to form a set of shared combined cooling circulation loop, and the heat generated at the two positions of the pumping source and the gain module are exchanged and cooled through the set of shared cooling circulation loop.

In summary, due to the adoption of the technical scheme, the invention has the beneficial effects that:

compared with the prior art, the composite cooling type immersion laser system designed by the invention innovatively realizes the effective cooling of the multi-point heat source for generating heat by the gain crystal and the pump source at the same time through one set of cooling circulation system, and the effective heat management is ensured by cooling the laser gain medium. On the other hand, the laser system stores the system heat of the multi-point heat source in the thermal phase change cooling material, thereby greatly improving the compactness of the system while realizing effective heat management and greatly reducing the volume and the weight of the system.

Drawings

The invention will now be described, by way of example, with reference to the accompanying drawings, in which:

FIG. 1 is a schematic diagram of an ultra-compact, lightweight composite cooling immersion high-energy laser system of the present invention;

FIG. 2 is a cross-sectional view of the gain module of an ultra-compact, lightweight composite cooled immersion high-energy laser system of the present invention taken along the Y-direction;

FIG. 3 is a cross-sectional view of the gain module of an ultra-compact, lightweight composite cooled immersion high-energy laser system of the present invention taken along the X-direction;

FIG. 4 is a schematic view of a compound cooling mode of the pump source of the present invention;

FIG. 5 is a schematic diagram of the stacking of pigtail pump sources on a composite cold plate according to the present invention.

In the figure: 1. the device comprises a resonant cavity total reflection mirror, 2, an immersion type laser gain module, 3, a pumping source composite cold plate, 4, a tail fiber pumping source, 5, a tail fiber pumping source transmission optical fiber, 6, a gain module light-transmitting port, 7, a resonant cavity output mirror, 8, output laser, 9, a circulating pump, 10, a circulating pipeline, 11, a collimation end cap, 12, a gain module heat exchange fin, 13, laser cooling liquid, 14, a gain medium crystal, 15, a thermal phase change cooling material, 16 and a composite cold plate heat exchange fin.

Detailed Description

In order to make the technical solutions of the present invention better understood, the technical solutions of the present invention are described below clearly and completely with reference to the accompanying drawings of the present invention, and based on the embodiments in the present application, other similar embodiments obtained by a person of ordinary skill in the art without making creative efforts shall fall within the protection scope of the present application.

In the present invention, unless otherwise expressly stated or limited, the terms "connected," "secured," and the like are to be construed broadly, and for example, "secured" may be a fixed connection, a removable connection, or an integral part; the connection can be mechanical connection, electrical connection, physical connection or wireless communication connection; they may be directly connected or indirectly connected through intervening media, or they may be connected internally or in any other suitable relationship, unless expressly stated otherwise. The specific meanings of the above terms in the present invention can be understood by those skilled in the art according to specific situations.

Example 1

As shown in fig. 1, fig. 1 is an ultra-compact lightweight composite cooling type immersion high-energy laser system, which includes a laser resonant cavity for generating laser oscillation feedback, an immersion laser gain module 2 for obtaining high gain, and a composite cooling pump module for outputting pump light, wherein the immersion laser gain module 2 and the composite cooling pump module share a set of cooling circulation system.

The laser resonator is used to generate laser oscillation feedback and obtain output laser light 8. In one embodiment, the laser resonant cavity structure mainly comprises a resonant cavity total reflection mirror 1 and a resonant cavity output mirror 7, and the resonant cavity total reflection mirror 1 and the resonant cavity output mirror 7 are respectively positioned at two sides of the whole optical path structure of the immersion type laser gain module 2.

The immersion laser gain module 2 is used to generate high laser gain. FIG. 2 is a cross-sectional view of an immersion laser gain module 2 of an ultra-compact lightweight composite cooled immersion high-energy laser system along the Y-direction. As shown in fig. 2, the immersion laser gain module 2 includes a plurality of arrayed gain medium crystals 14 fixedly stacked. A flow channel having a constant thickness is formed between the gain medium crystals 14, and the surface of the gain medium crystal 14 is cooled by the laser coolant 13 flowing in the flow channel.

In this embodiment, a scheme of arranging a plurality of gain medium crystals 14 in an array is adopted, and heat is dissipated between the gain medium crystals 14 by using the flowing laser cooling liquid 13. The scheme can obtain higher laser gain in unit volume while reducing the thermal load of the monolithic crystal. It should be noted that the number of the gain medium crystals 14 in this embodiment may be several, several tens, or several hundreds, and the actual number may be set according to the index requirement of the laser system.

Meanwhile, in the embodiment, the laser cooling liquid 13 preferably has a liquid with a better cooling effect, a better thermodynamic property and a weaker absorption on the output main laser and the pump light as the cooling liquid, and does not affect the output power of the laser. The coolant flows through the microchannels between the gain medium crystals 14, and carries away the heat generated by the gain medium crystals 14.

FIG. 3 is a cross-sectional view of the immersion laser gain module 2 of the ultra-compact lightweight composite cooled immersion high-energy laser system along the X-direction. Referring to fig. 2 and 3, gain module heat exchange fins 12 having the same thickness as the gain medium crystal 14 are respectively disposed at the front end and the rear end of the gain medium crystal 14, and a certain amount of thermal phase change cooling material 15 is stored in each gain module heat exchange fin 12. The gain module heat exchange fins 12 have two functions: on one hand, heat generated by the gain medium crystal 14 in the laser cooling liquid 13 is rapidly replaced into the thermal phase change cooling material 15, and on the other hand, the flow field of the laser cooling liquid 13 can be homogenized uniformly.

In the embodiment, the gain module 2 is internally provided with the gain module heat exchange fins 12 at two ends of the gain medium crystal 14, so that the problems of rapid heat exchange and flow field shaping can be innovatively solved.

The thermal phase change cooling material 15 is preferably a phase change material having a large heat storage capacity such as an alkane, a polyol, a hydrated salt, and the like in one embodiment. In a preferred embodiment, a phase change material having a capacity of absorbing and storing latent heat of greater than or equal to 100KJ/KG may be considered to have a large heat storage capacity.

The immersion type laser gain module 2 can realize a thermal management closed loop to a certain extent, namely, in the laser output period, heat is stored into the thermal phase change cooling material 15 through the laser cooling liquid 13, the thermal phase change cooling material 15 has the characteristics of quickly absorbing heat and gradually releasing heat to the environment, and the thermal phase change cooling material can recover automatically without extra special cooling in the laser non-output stage.

The gain medium crystal 14 in the laser system of the present invention is preferably an isotropic material, such as Nd: YAG material, and has no particular selection characteristics for the polarization state of the pump laser.

The composite cooling pumping module is mainly used for injecting pumping light into the immersion type laser gain module 2, so that the population inversion is realized to obtain laser gain, and meanwhile, the high-efficiency direct liquid cooling is realized. The composite cooling pumping module comprises a pumping source composite cold plate 3, a tail fiber pumping source 4, a tail fiber pumping source transmission optical fiber 5, a circulating pump 9, a circulating pipeline 10 and a collimation end cap 11.

And pump light output by the tail fiber pump source 4 is shaped by the tail fiber pump source transmission fiber 5 and the collimation end cap 11, and then is injected into the gain medium crystal 14 through the gain module light through ports 6 on two side surfaces to obtain the population inversion. Feedback oscillation is obtained under the action of a resonant cavity formed by the laser resonant cavity total reflection mirror 1 and the resonant cavity output mirror 7, and output laser 8 is output from one end of the resonant cavity output mirror 7 after a certain output threshold value is reached.

The pump system has the advantage that the compactness of the system is improved by adopting a composite cooling mode. Fig. 4 is a schematic diagram of a composite cooling method of the pump source of the present invention, and as shown in fig. 4, the working principle of the composite cooling method is as follows: the pump source composite cold plate 3 and the immersion type laser gain module 2 share the laser cooling liquid 13, the laser cooling liquid 13 is cooled by gain module heat exchange fins 12 in the immersion type laser gain module 2 under the action of the circulating pump 9 and then flows into the pump source composite cold plate 3 through the circulating pipeline 10, on the other hand, the tail fiber pump source 4 is fixed on the surface of the composite cold plate 3 through heat conduction silicone grease, heat generated by the tail fiber pump source 4 is transferred to the laser cooling liquid 13, meanwhile, composite cold plate heat exchange fins 16 are also arranged inside the pump source composite cold plate 3, and the composite cold plate heat exchange fins 16 also store the thermal phase change cooling material 15, so that the heat in the pump source is further transferred and exchanged into the thermal phase change cooling material 15.

In one embodiment, the thermal phase change cooling material 15 stored in the gain module heat exchange fins 12 and the thermal phase change cooling material 15 stored in the composite cold plate heat exchange fins 16 are the same material, or different materials with large heat storage capacity may be used, so that a rapid heat storage function can be completed in actual operation.

It can be seen that there are two heat sources in the whole high-energy laser system, namely gain crystal heat generation and pump source heat generation. In the embodiment, the same cooling loop is adopted for heat release of the two heat sources, and the system heat is stored in the thermal phase change cooling material. Namely, under the action of the circulating pump 9, the laser cooling liquid 13 circulates in the system loop, rapidly takes heat from two heat source areas and stores the heat in the thermal phase change cooling material 15 in the heat exchange fins.

The embodiment of the invention preferably uses a diode tail fiber laser with high electro-optical efficiency as the tail fiber pump source 4.

Fig. 5 is a schematic diagram of the stacking manner of the pigtail pump source 4 on the pump source composite cold plate 3 according to the present invention. The stacking mode of the pigtail pump source 4 on the pump source composite cold plate 3 is the double-sided array full-spread mode shown in fig. 5, so that the heat dissipation efficiency is improved as much as possible.

When the tail fiber pump source 4 is fully laid on the pump source composite cold plate 3 in a double-sided array manner as shown in fig. 5, correspondingly, both sides of the pump source composite cold plate 3 are connected with the immersion type laser gain module 2 through tail fiber pump source transmission optical fibers 5 as shown in fig. 1, so as to transmit pump light; meanwhile, the pump source composite cold plate 3 is also connected to the immersion type laser gain module 2 through a circulation pipe 10, as shown in fig. 1 and 4, for circulating a cooling liquid.

It should be noted that, in the embodiment shown in fig. 1, the laser system includes two immersion

laser gain modules

2 and 2 pump source composite cold plates 3, which are connected in a closed loop manner as described above. In other embodiments, the number of immersion laser gain modules 2 and pump source composite cold plates 3 may be increased or decreased depending on the specifications and performance requirements of the laser system.

Through the structural design of the composite cooling type immersion laser system, compared with the prior art, the laser system innovatively realizes effective cooling of heat generation of the gain crystal and heat generation of the pumping source through one set of cooling circulation system, and stores the system heat generation in the thermal phase-change material, so that the compactness of the system is greatly improved while effective heat management is realized, and the volume and the weight of the system are greatly reduced. Relevant experimental data show that aiming at a 20kW composite cooling type immersion laser system (30% of electro-optic efficiency, 20% of heavy water laser cooling liquid, 30kg of thermal phase change cooling material with the heat storage capacity of 100kJ/kg, 40kg of weight of a pumping source, 20kg of gain module and 10kg of other components are estimated according to the existing level), the single light emitting time of the laser system is 30 seconds, the single light emitting heat of the system is 2000kJ, all 2000kJ heat is stored in the thermal phase change cooling material after the single light emitting is completed, the total weight of the whole system is 120kg, the power-weight ratio reaches 167W/kg, and the improvement is approximately one order of magnitude compared with the existing solid laser system.

The above description is only a preferred embodiment of the present invention, and is not intended to limit the scope of the present invention, and all modifications and equivalents of the present invention, which are made by the contents of the present specification and the accompanying drawings, or directly/indirectly applied to other related technical fields, are included in the scope of the present invention.

Any feature disclosed in this specification (including any accompanying claims, abstract) may be replaced by alternative features serving equivalent or similar purposes, unless expressly stated otherwise. That is, unless expressly stated otherwise, each feature is only an example of a generic series of equivalent or similar features.

Claims

1. An ultra-compact lightweight composite cooled immersion high-energy laser system, comprising: the device comprises a laser resonant cavity for generating laser oscillation feedback, an immersion type laser gain module (2) for obtaining high gain, and a composite cooling pumping module for outputting pumping light, wherein the immersion type laser gain module (2) and the composite cooling pumping module share a composite cooling circulating system.

2. The ultra-compact lightweight composite cooled immersion high-energy laser system according to claim 1, wherein the laser resonator comprises a resonator all-mirror (1) and a resonator output mirror (7), and the resonator all-mirror (1) and the resonator output mirror (7) are respectively located on both sides of the overall structure of the immersion laser gain module (2).

3. The ultra-compact lightweight composite cooled immersion high-energy laser system according to claim 2, wherein the immersion laser gain module (2) comprises a plurality of gain medium crystals (14) fixedly stacked in an array, a flow channel is formed between each gain medium crystal (14), and the surface of each gain medium crystal (14) is cooled by a laser cooling liquid (13) flowing in the flow channel.

4. The ultra-compact lightweight composite cooling immersion type high-energy laser system as claimed in claim 3, wherein gain module heat exchanging fins (12) having a thickness corresponding to that of the gain medium crystal (14) are respectively provided at the front end and the rear end of the gain medium crystal (14), and each gain module heat exchanging fin (12) stores therein a thermal phase change cooling material (15).

5. The ultra-compact lightweight composite cooled immersion high-energy laser system according to claim 4, wherein the thermal phase change cooling material (15) is one of an alkane, a polyol or a hydrated salt.

6. The ultra-compact lightweight composite cooled immersion high-energy laser system according to claim 4, wherein the composite cooling pump module is used for injecting pump light into the immersion laser gain module (2), and comprises a pump source composite cold plate (3), a pigtail pump source (4), a pigtail pump source transmission fiber (5), a circulating pump (9), a circulating pipeline (10), and a collimation end cap (11) connected with the pigtail pump source transmission fiber (5).

7. The ultra-compact lightweight composite cooling immersion type high-energy laser system according to claim 6, wherein the pump light output by the pigtail pump source (4) is transmitted by a pigtail pump source transmission optical fiber (5) and shaped by a collimation cap end (11), and then is injected into a gain medium crystal (14) through gain module light-passing ports (6) on two sides to obtain population inversion; meanwhile, feedback oscillation is obtained under the action of the resonant cavity, and output laser (8) is generated for output after the output threshold is reached.

8. The ultra-compact lightweight composite cooled immersion high-energy laser system according to claim 6, characterized in that the inside of the pump source composite cold plate (3) is provided with composite cold plate heat exchanging fins (16), and the inside of the composite cold plate heat exchanging fins (16) stores the thermal phase change cooling material (15).

9. The ultra-compact lightweight composite cooled immersion high-energy laser system of claim 8, wherein the immersion laser gain module (2) and the composite cooling pump module share a composite cooling circulation system comprising: the pump source composite cold plate (3) and the immersion type laser gain module (2) share laser cooling liquid (13), the laser cooling liquid (13) is cooled by gain module heat exchange fins (12) in the immersion type laser gain module (2) under the action of a circulating pump (9) and then flows into the pump source composite cold plate (3) through a circulating pipeline (10), meanwhile, heat generated by a tail fiber pump source (4) fixed on the surface of the pump source composite cold plate (3) is transferred into the laser cooling liquid (13), and heat in the tail fiber pump source (4) is transferred and exchanged into a thermal phase change cooling material (15).

10. The ultra-compact lightweight composite cooled immersion high-energy laser system according to claim 9, wherein the pigtail pump source (4) is stacked on the pump source composite cold plate (3) in a double-sided array full-spread manner.